package com.study.spmongodb.wwj.thread2.char04;

/**
 * @author MI
 * @version 1.0
 * @date 2020/12/7 19:35
 */
public abstract class Observer {

    protected Subject subject;

    public Observer(Subject subject) {
        this.subject = subject;
        this.subject.attach(this);
    }

    public abstract void update();

}
